Merge pull request yangxikun#25 from plantfansam/baggage

Add Baggage and Propagator

Makefile

@@ -15,7 +15,7 @@ openresty-unit-test:
 	$(CONTAINER_ORCHESTRATOR) exec $(CONTAINER_ORCHESTRATOR_EXEC_OPTIONS) -- openresty bash -c 'cd /opt/opentelemetry-lua && prove -r'
 
 lua-unit-test:
-	$(CONTAINER_ORCHESTRATOR) run $(CONTAINER_ORCHESTRATOR_EXEC_OPTIONS) -- openresty-test bash -c 'cd /opt/opentelemetry-lua && ./busted-runner'
+	$(CONTAINER_ORCHESTRATOR) run $(CONTAINER_ORCHESTRATOR_EXEC_OPTIONS) -- openresty-test  bash -c 'cd /opt/opentelemetry-lua && ./busted-runner'
 
 openresty-build:
 	$(CONTAINER_ORCHESTRATOR) build

busted-runner

@@ -3,7 +3,7 @@
 package.path = './lib/?.lua;./lib/?/?.lua;./lib/?/init.lua' .. package.path
 
 _TEST = true
-_RUN_SLOW_TESTS = os.getenv("RUN_SLOW_TESTS") or false
+_RUN_SLOW_TESTS = true
 
 -- Set up global tracer
 Global = require("opentelemetry.global")

lib/opentelemetry/baggage.lua

@@ -0,0 +1,67 @@
+local util = require("opentelemetry.util")
+
+local _M = {
+}
+
+local mt = {
+    __index = _M
+}
+
+function _M.new(values)
+    return setmetatable({ values = values or {} }, mt)
+end
+
+--------------------------------------------------------------------------------
+-- Set a value in a baggage instance. Does _not_ inject into context
+--
+-- @name                name for which to set the value in baggage
+-- @value               value to set must be string
+-- @metadata            metadata to set in baggage (string)
+-- @return              baggage
+--------------------------------------------------------------------------------
+function _M.set_value(self, name, value, metadata)
+    local new_values = util.shallow_copy_table(self.values)
+    new_values[name] = { value = value, metadata = metadata }
+    return self.new(new_values)
+end
+
+--------------------------------------------------------------------------------
+-- Get value stored at a specific name in a baggage instance
+--
+-- @name                name for which to set the value in baggage
+-- @return              baggage
+--------------------------------------------------------------------------------
+function _M.get_value(self, name)
+    if self.values[name] then
+        return self.values[name].value
+    else
+        return nil
+    end
+end
+
+--------------------------------------------------------------------------------
+-- Remove value stored at a specific name in a baggage instance.
+--
+-- @name                name to remove from baggage
+-- @return              baggage
+--------------------------------------------------------------------------------
+function _M.remove_value(self, name)
+    local new_values = util.shallow_copy_table(self.values)
+    new_values[name] = nil
+    return self.new(new_values)
+end
+
+--------------------------------------------------------------------------------
+-- Get all values in a baggage instance. This is supposed to return an immutable
+-- collection, but we just return a copy of the table stored at values.
+--
+-- @context             context from which to access the baggage (defaults to
+--                      current context)
+-- @return              table like { keyname = { value = "value",
+--                                               metadata = "metadatastring"} }
+--------------------------------------------------------------------------------
+function _M.get_all_values(self)
+    return util.shallow_copy_table(self.values)
+end
+
+return _M

lib/opentelemetry/baggage/propagation/text_map/baggage_propagator.lua

@@ -0,0 +1,123 @@
+--------------------------------------------------------------------------------
+--
+-- See https://w3c.github.io/baggage/ for details.
+--
+--------------------------------------------------------------------------------
+
+local baggage = require("opentelemetry.baggage")
+local text_map_getter = require("opentelemetry.trace.propagation.text_map.getter")
+local text_map_setter = require("opentelemetry.trace.propagation.text_map.setter")
+local util = require("opentelemetry.util")
+
+local _M = {
+}
+
+local mt = {
+    __index = _M,
+}
+
+local baggage_header = "baggage"
+
+function _M.new()
+    return setmetatable(
+        {
+            text_map_setter = text_map_setter.new(),
+            text_map_getter = text_map_getter.new()
+        }, mt)
+end
+
+-------------=------------------------------------------------------------------
+-- Set baggage header on outbound HTTP request header.
+--
+-- @param context       context storage
+-- @param carrier       nginx request
+-- @param setter        setter for interacting with carrier
+-- @return nil
+--------------------------------------------------------------------------------
+function _M:inject(context, carrier, setter)
+    setter = setter or self.text_map_setter
+    local bgg = context:extract_baggage()
+    local header_string = ""
+    for k, v in pairs(bgg.values) do
+        local element = k .. "=" .. v.value
+        if v.metadata then
+            element = element .. ";" .. v.metadata
+        end
+        element = element .. ","
+        header_string = header_string .. element
+    end
+
+    -- trim trailing comma
+    header_string = header_string:sub(0, -2)
+
+    setter.set(
+        carrier,
+        baggage_header,
+        util.percent_encode_baggage_string(header_string)
+    )
+end
+
+--------------------------------------------------------------------------------
+-- Extract baggage from HTTP request headers.
+--
+-- @context             current context
+-- @carrier             ngx.req
+-- @return              new context with baggage associated
+--------------------------------------------------------------------------------
+function _M:extract(context, carrier, getter)
+    getter = getter or self.text_map_getter
+    local baggage_string = getter.get(carrier, baggage_header)
+    if not baggage_string then
+        return context.new(context.entries)
+    else
+        baggage_string = util.decode_percent_encoded_string(baggage_string)
+    end
+
+    local baggage_entries = {}
+    -- split apart string on comma and build up baggage entries
+    for list_member in string.gmatch(baggage_string, "([^,]+)") do
+        -- extract metadata from each list member
+        local kv, metadata = string.match(list_member, "([^;]+);(.*)")
+
+        -- If there's no semicolon in list member, then kv and metadata are nil
+        -- and we need to correct that
+        if not kv then
+            kv = list_member
+            metadata = ""
+        end
+
+        -- split apart k/v on equals sign
+        for k, v in string.gmatch(kv, "(.+)=(.+)") do
+            if self.validate_baggage(k, v) then
+                baggage_entries[k] = { value = v, metadata = metadata }
+            else
+                ngx.log(ngx.WARN, "invalid baggage entry: " .. k .. "=" .. v)
+            end
+        end
+    end
+
+    local extracted_baggage = baggage.new(baggage_entries)
+    return context:inject_baggage(extracted_baggage)
+end
+
+--------------------------------------------------------------------------------
+-- Check to see if baggage has both key and value component
+--
+-- @key                 baggage key
+-- @value               baggage value
+-- @return              boolean
+--------------------------------------------------------------------------------
+function _M.validate_baggage(key, value)
+    return (key and value) ~= nil
+end
+
+--------------------------------------------------------------------------------
+-- Fields that will be used by the propagator
+--
+-- @return              table
+--------------------------------------------------------------------------------
+function _M.fields()
+    return { "baggage" }
+end
+
+return _M

lib/opentelemetry/context.lua

@@ -1,3 +1,4 @@
+local baggage = require("opentelemetry.baggage")
 local otel_global = require("opentelemetry.global")
 local non_recording_span_new = require("opentelemetry.trace.non_recording_span").new
 local noop_span = require("opentelemetry.trace.noop_span")
@@ -11,7 +12,7 @@ local mt = {
 }
 
 local context_key = "__opentelemetry_context__"
-
+local baggage_context_key = "__opentelemetry_baggage__"
 
 --------------------------------------------------------------------------------
 -- Create new context with set of entries
@@ -92,6 +93,25 @@ function _M.set(self, key, value)
     return self.new(vals, self.sp)
 end
 
+--------------------------------------------------------------------------------
+-- Inject baggage into current context
+--
+-- @baggage             baggage instance to inject
+-- @return              context
+--------------------------------------------------------------------------------
+function _M.inject_baggage(self, baggage)
+    return self:set(baggage_context_key, baggage)
+end
+
+--------------------------------------------------------------------------------
+-- Extract baggage from context
+--
+-- @return              baggage
+--------------------------------------------------------------------------------
+function _M.extract_baggage(self)
+    return self:get(baggage_context_key) or baggage.new({})
+end
+
 function _M.with_span(self, span)
     return self.new({}, span)
 end